Humpback whales feed in Icy Strait above North Chichagof Island, an important travel corridor for many marine mammals, including federally threatened Steller's sea lions. The area's coastal marshes and mudflats are important as resting areas for shorebirds and waterfowl, and provide spring feeding areas for brown bears. Marbled murrelets feed in large numbers within the waters of Icy Strait and nest in the island's coastal old growth forest.